1. Field of the Invention
The present invention relates to a process for preparing a multilayer interconnection in a semiconductor device.
2. Description of the Prior Art
It has been limited to form a layer insulating film which can be formed at a relatively low temperature when a material having a relatively low softening temperature such as aluminum or aluminum alloy is used for inner wirings in the preparation of such multilayer interconnection. In usual, a silicon oxide film formed by a chemical vapor deposition process or a sputtering process has been used as the layer insulating film. Recently a nitride film formed by a plasma enhanced chemical vapor deposition process has begun to be used because of excellent step-coverage on a step portion, low density of pin-holes and capability of processing through-holes by a dry-etching. When the multilayer interconnection is commercially formed, the mutual diffusion between the interconnection layer made of aluminum or aluminum alloy and the nitride film is resulted to disadvantageously cause short-circuit between the interconnections for the different layers.